I take valtrex for cold sores. its worked really good for me but i have had the cold sore i have now for over month and cant get rid of it?

Cold sores are usually caused by viruses & usually resolve within 10-14 days or less, so it is worrisome that it has been present that long. I would worry about a secondary infection or another complication & recommend a Dr exam in person to evaluate it . You could try applying topical antibiotics 3 times a day in the mean time, after cleaning with antibacterial soap